Currently, dual mode devices are envisioned to support Internet access via a wide array of different radio access technologies. The goal is to provide ubiquitous coverage and seamless connectivity irrespective of which radio access technology is available.
FIG. 1 shows a conventional dual mode mobile terminal system 100 including a dual mode mobile terminal 105. The two modes to which “dual mode” refers are a network which complies with IEEE 802.11 and a network which complies with one or more of the Third Generation (3G) standards. The dual mode mobile terminal 105 communicates with the Internet 110 via (1) an IEEE 802.11 access point/router equipment 115 over an IEEE 802.11 air interface, or (2) a 3G universal terrestrial radio access network (UTRAN) base station 120 via a 3G air interface.
A difficulty associated with such a conventional system 100 is that, due to architectural differences, there is no common control entity to manage the physical handover process between the IEEE 802.11 and 3G radio networks. This results in a complex association between the handover control functions of each network. For example, the coordination and logic required to transfer the radio connection from the IEEE 802.11 network to the 3G network is significantly different from what is required to transfer the radio connection from the 3G network to the IEEE 802.11 network. Note that the handover in this sense can also be viewed as cell reselection or re-association. What is needed is a system and method for seamlessly and simply facilitating wireless connectivity between two different radio access technologies.
Another problem is that 802.11 access devices require service from 802.11 access points that have dedicated terrestrial trunks to the Internet. When an 802.11 access point is unavailable, Internet services are not provided to the 802.11 access device. Since 802.11 access points are generally not provisioned to provide ubiquitous coverage the mobile user will often have access to Internet services. Further, dedicated terrestrial links providing Internet connectivity to the 802.11 access points in certain deployment scenarios are expensive to install and maintain. In these cases, an alternative to the terrestrial link is needed.